Conventionally, there has been known a music reproduction apparatus with game feature, which detects a user operation directed to an image moving on a display screen in time with the reproduction of music, evaluates the suitability (accuracy) of timing of the user operation, and based on a result of the evaluation, generates an effect sound or controls a displayed content on the screen. See, for example, Japanese Laid-open Patent Publication No. 2001-232058.
The above music reproduction apparatus (game machine) is stored beforehand with an event data string synchronous with music, and displays an image on a display screen according to the event data, while reproducing the music. When a user performs an operation directed to the image moving according to the event data, a difference between a moving position of the image and a user operation position on the screen is detected, and the suitability (accuracy) of user operation timing is evaluated.
To perform predetermined control such as sounding control or screen display control in accordance with the determined suitability of the user operation timing, it is necessary to carry out beforehand an authoring process to prepare an event data string synchronous with music, which poses a problem.